Merge pull request #85 from akx/unsafe-mode

Add --unsafe

Author: MarcoGorelli

auto_walrus.py

@@ -2,6 +2,7 @@
 
 import argparse
 import ast
+import dataclasses
 import os
 import pathlib
 import re
@@ -30,6 +31,12 @@
 )
 
 
+@dataclasses.dataclass
+class Config:
+    line_length: int
+    unsafe: bool = False
+
+
 def name_lineno_coloffset_iterable(
     tokens: Iterable[Token],
 ) -> list[tuple[str, int, int]]:
@@ -193,6 +200,7 @@ def related_vars_are_unused(
 
 def visit_function_def(
     node: ast.FunctionDef,
+    config: Config,
 ) -> list[tuple[Token, Token]]:
     names = set()
     assignments: set[Token] = set()
@@ -204,7 +212,7 @@ def visit_function_def(
     related_vars: dict[str, list[Token]] = {}
     in_body_vars: dict[Token, set[Token]] = {}
 
-    for _node in node.body:
+    for _node in ast.walk(node) if config.unsafe else node.body:
         if isinstance(_node, ast.Assign):
             process_assign(_node, assignments, related_vars)
         elif isinstance(_node, ast.If):
@@ -255,7 +263,7 @@ def visit_function_def(
 
 def auto_walrus(
     content: str,
-    line_length: int,
+    config: Config,
 ) -> str | None:
     lines = content.splitlines()
     try:
@@ -266,7 +274,7 @@ def auto_walrus(
     walruses = []
     for node in ast.walk(tree):
         if isinstance(node, ast.FunctionDef):
-            walruses.extend(visit_function_def(node))
+            walruses.extend(visit_function_def(node, config))
     lines_to_remove = []
     walruses = sorted(walruses, key=lambda x: (-x[1][1], -x[1][2]))
 
@@ -290,7 +298,7 @@ def auto_walrus(
             line_with_walrus = left_bit + replace + right_bit
         else:
             line_with_walrus = left_bit + "(" + replace + ")" + right_bit
-        if len(line_with_walrus) > line_length:
+        if len(line_with_walrus) > config.line_length:
             # don't rewrite if it would split over multiple lines
             continue
         # replace assignment
@@ -361,18 +369,24 @@ def main(argv: Sequence[str] | None = None) -> int:  # pragma: no cover
         required=False,
         default=r"^$",
     )
+    parser.add_argument(
+        "--unsafe",
+        action="store_true",
+        help="Also process if statements inside other blocks (like for loops)",
+    )
     # black formatter's default
     parser.add_argument("--line-length", type=int, default=88)
     args = parser.parse_args(argv)
     paths = [pathlib.Path(path).resolve() for path in args.paths]
 
     # Update defaults from pyproject.toml if present
-    config = {k.replace("-", "_"): v for k, v in _get_config(paths).items()}
-    parser.set_defaults(**config)
+    defaults = {k.replace("-", "_"): v for k, v in _get_config(paths).items()}
+    parser.set_defaults(**defaults)
     args = parser.parse_args(argv)
 
     ret = 0
 
+    config = Config(line_length=args.line_length, unsafe=args.unsafe)
     for path in paths:
         if path.is_file():
             filepaths = iter((path,))
@@ -392,10 +406,7 @@ def main(argv: Sequence[str] | None = None) -> int:  # pragma: no cover
                     content = fd.read()
             except UnicodeDecodeError:
                 continue
-            new_content = auto_walrus(
-                content,
-                line_length=args.line_length,
-            )
+            new_content = auto_walrus(content, config)
             if new_content is not None and content != new_content:
                 sys.stdout.write(f"Rewriting {filepath}\n")
                 with open(filepath, "w", encoding="utf-8") as fd:

tests/main_test.py

@@ -7,6 +7,7 @@
 
 import pytest
 
+from auto_walrus import Config
 from auto_walrus import auto_walrus
 from auto_walrus import main
 
@@ -89,7 +90,7 @@
     ],
 )
 def test_rewrite(src: str, expected: str) -> None:
-    ret = auto_walrus(src, 88)
+    ret = auto_walrus(src, Config(line_length=88))
     assert ret == expected
 
 
@@ -125,10 +126,24 @@ def test_rewrite(src: str, expected: str) -> None:
     ],
 )
 def test_noop(src: str) -> None:
-    ret = auto_walrus(src, 40)
+    ret = auto_walrus(src, Config(line_length=40))
     assert ret is None
 
 
+@pytest.mark.parametrize(
+    ("src", "expected"),
+    [
+        (
+            'def foo(data):\n    if True:\n        foo = data.get("blah")\n        if foo:\n            return foo\n    return data',
+            'def foo(data):\n    if True:\n        if (foo := data.get("blah")):\n            return foo\n    return data',
+        ),
+    ],
+)
+def test_rewrite_unsafe(src: str, expected: str) -> None:
+    ret = auto_walrus(src, Config(line_length=88, unsafe=True))
+    assert ret == expected
+
+
 ProjectDirT = Tuple[pathlib.Path, List[pathlib.Path]]
 
 SRC_ORIG = "def foo():\n    a = 0\n    if a:\n        print(a)\n"